Air-venting valve for hot-water systems



June 6, 1944. J. UPTON EI'AL 2,350,947

- N AIR VENTING VALVE FOR HOT WATER SYSTEMS Fil'egl March 26, 1941 2 Sheets-Sheet 2 S IIII'IIIII IIIIIIIIIIIIIII 174 304- 2 B 198 4 i A 190 I186 i 192 I84 #80 Imren'lors Patented June 6, 1944 AIR-VENTING-VALVE FOR HOT WATERF.

. SYSTEMS, a John Upton, Cambridge, and Warren '1. Ferguson; Wahan, Mass; assignors to-Anderson Products, Inc., CambridgmMa'ssg a corporation of Massachusetts Application inst 26, 194 Serial No. 385,234 14 Claims. (01. 137-422) V This invention relates to hot water'hea'ting systems and is particularly concerned with a means and method of eliminating. trapped air from radiators, or such other places. as it may accumulate. I

In hot water heatingsystems, at the outset of operation there is always a certain amount of air distributed throughout the water After a period of use, this air gradually collects in theiupper portions of the system and particularly in the tops of the radiators. Those radiatorsthat are onthe upper floors usually accumulate more air than those down below. l

If the system has a gravity'expansion tank located above the highest radiator, a slight amount of the air will escape through this oulet,,..but the largest portion of the air becomes trappedin the various radiators.

i In the sealed hotwater systems which utilize an expansion tank, the trapped air similarly accumulates in the radiators so. that the problem is present in both types ofsystems.

As air accumulates in a radiator, the heating efliciency is diminished as the water content is reduced. Therefore, it, is essential that theair be eliminated so that the radiators may remain substantiallyfull. u M

Heretofore it has been, customary to eliminate air from the radiators periodically through the use of a manually controlled valve; Hot water radiators ordinarily have a small ne'edle'valve 1o.-'

cated at the top which may be opened [to permit the escape of air as it maybenecessary. a

Many attempts have been made to provide .a valve which will automatically vent air as itmay accumulate in a radiator and at the sam time prevent any escape of water. i M

One of the objects of the inventiomtherefore, is to provide a valve which maybe attached to a hot water radiator to automatically vent air from the upper portions thereof 'as it may accumulate, without permitting the escape or foverfioyv of water. Similarly, such a valve'could be used at any other point whereair rnight be trapped, Another object of the invention is'topr ea valve which will operate autornaticallyjrom time to time to'permit thee'scape of air'froin the is diator at a rate greater than the "rate or air accumulation, so that if the valve is attached "to a radiator which is, 'say, only-half full of water, the air will be vented therefrom gradually by the intermittent operation of the valve. This assumes, of course, that sufficient water'pressur'e' is in the system to force the water upwardly in the radiator.

Another object of the is to provide a specialfitting whereby the valve maybe suitably connected to a radiator, the fitting including a manually operated valve mechanism which will permit quick venting 'of the air from the radiator at the time of initially 'filling the system or a't the a start of the heating season and before the automatic valves are placed in operation. e The invention also contemplates the series er steps that take "place in each heating cycl to result'in the expulsion of the trapped air littleby little as the cyclesarerepeate d.

Another object of the invention is to provide an air venting valve which will operate successfully to vent air from all radiators regardless of location.

' These and other objects of the invention will become more apparent as the description proceeds with the aid of the'acccmpanyin'g. drawings, in

which i I Fig. 1 is a diagrammatic showing of atypical gravity hot water heating systemutilizinga closed or sealed expansion tank;

Fig-. 2 is a cross-section of the automatic venting valve; M Fig. '3 is a cross-sectional'detail of the valve connection; v Fig. 4 isan enlarged detail of the valve members, showing the partsin normal; non-venting positiom. i Fig.5 is. an enlarged detail of thevvalve members withthe parts in the position assumed at thelend of theupward movementof the movabl valve member and float; I Figrfi is an enlarged detail .of, the valve members with the parts in the position assumed just priort ventins; a e I Fig.,7 is an enlarged detail oi the valve members th t e erts n venting os tiq Rig, 8 is amodified form of,,valve;

' a d are d a ed T W n ed-i 1 valveaction in venting airjand correspond to Figs. 5, .2mm... Fig. 12 is another'modification' oij' the valve n u' ti n. 1 1 V I'n'Fig. 1 a boiler, represented at 2, is 'iired by ei v'cbnyenient sourceof heat, which'inj the pres entinstance issh'own as men burners Bauer 2 nasextending therefrom a riser a ranching out into header 6, which in turn extends to twe risers 8 and Ill. Connected "t6 risers 8 and ID are radig ators l2" and l t'res'pe'ctively'. From bother the radiators extend return lines. Hi and I8, joinin in a cemmon return :20 at 'tHeIower-part' of the boiler; A sealed expansion tankl22 is connected to header 6 by pipe 24. On each of radiators l2 and 14 man automatic venting valve 26 which will hereinafter be de scribed in more detail. These valves 26 are connected to the radiators by a special connection 28 which will likewise be more fully'described hereinafter.

In the operation of a system .of t his type, water from a feed line 30 is admitted to the boiler by valve 3| and the entire system is gradually filled as air is vented through the special connections v 28. When radiators 12 and I4 have been filled, special connections 28 are closed and the system is sealed. In the meanwhile, during filling, water Float 86 is in turn supported on the upper end has flowed into compression tank' 22 until the pressure of air in the top portionof the tank balances the water pressure to maintain the water in the topmost portions of the system.

With the system in this condition, it is ready for operation. The heating mechanism 3 in the typical instance will be automatically started and stopped through the suitable location of a thermostatic room control of the usual wellknown type. I

As the wateryin response tothe thermostat, is periodically heated, it circulates through the mains 4, 6, 8 and II) to the radiators and returns to the boiler through ,returnmain 20 for re-, heating and recirculation. Such expansion of the water as may take place during a heatin cycle is provided .for through theopeiation of compression tank 22,in which the air above the water surface .is compressed as ,much' as necessary. The system= as described would operate indefinitely were it notzfor the fact that after a time the air in the water gradually rises and accumulates'in the'upper portion of the radiators. and as this happens the heatin efliciency is lowered. Therefore, it is essential that the trapped air be vented from time to time and throu h'the'use of valves 26 this result is fully accomplishe I J a I Referring now to Fig. '2, the valve construction will be more particularly described. The 'valve comprises a base 40 having a downwardly'ex tending threadednipple 42' adapted to make' connection with the radiator, The base is circular and terminatesin a flange '44 recessed at-46 to receive'a gasket 48 on which rests flange Qof a covering shell 52.. Flan e.5ll is held ti htly. in place by lock nut 54 which is in screw threaded engagementwiththe base, as shown. Shell 52 has an opening at 56 for the escape ofairto'tbe atmosphere. f

In screw threaded engagement with the interior of the base is a perforated supporting plate anda bellows -;.1 8;mounted thereorp, .Bellows; 10

isclosed at-its rupper end by'a member 12 .of; particular; construction. Through the: center; of member: 12, is a passage 1.4 1 which ;terminates;at its lower and upper ends to form valve seats 16. and 18. The'upperportion ofshell 66 .has a portf80 locatedat'any. convenient place therein.

It is apparent that" any air entering through nipple 42 must pass through plate 58, the lower portion'of shell 66, through port 16, then of adjustable stem 62.

Valve. member .84, which depends downwardly toward valve seat 18, is carried by support 92,

which-is adjustably mounted at the top of shell 66 by threaded engagement therewith as shown.

. ,In order that this valve may operate to vent air, it is'necessary that there be a particular adjustment of valve members 82 and 84 with relationto the lower and upper valve seats 16 and 18.; {The method ofadjustment is as follows: Valve member. .is.moved upwardly until it is entirely clear of valve seat 18. Stem 62 is then screwed upwardly, carrying with it floatiiB and valve member. 82 until the latter is very close to valve seat 16 or in actual engagement with it. If the adjustment is such that there is a slight clearance between valve pin 8.2 and seat 16, the pressure within thefvalve, that is normally pres-. ent during operation, will result in driving'float 86 and valve pin .82 upwardly into closed position. If, on the other hand, the-adjustment is such that valve pin 82 is actually in engagement with valve' seat 16,. then, of. course, the valveis normally closed at all pressures. The operation of the valve is the same regardless of this initial setting, because the float will always lift. to closed position under normal operating conditions. Thesetting of valve member 12, as determined by the position of valve pin 82, contrials the pressure, necessary within the lower part of shell 66 before further elongation of bellows 10 can take. place.

j .WithQthis accomplished, support- 92 is then screwedfdownwardly until valve member -84 is within a very small distance of valve seat 18, as in Fig. 4., It will. be seen by this arrangement that. under conditions of low pressure within thevalve, port 14 will be normally closed by engagementof valve member 82 with valve seat 16.. If the water level in the radiator has dropped, it is obvious that the interior of shell 66 will contain air only and there will be no buoyant .efi'ect on float 86. During the heating part of the heating cycle, the-water in the system expands and this in turn'results in,an increase in pressure. in the trapped air, The adjustment 'ofstem 62 is such-that the increased air pres sure'within the lower part of shell 66 during a heating cycle will besuflicient to cause further elongation. ofbellows l0, driving member'lZ upwardly-untilvalve seat 18 is in, engagement with valve.member 84.- During the upward movement of member 12, float 86"and .valve member 82 are carriedalong with it, leaving the support on the top end of stem 62. Member 82 remains in engagement with seat, IS-during the upward movementyof'member-n until valve member 84 and valveseat [8 meet, as shownin Fig. 5.

. -As soon as valve seat 18 has made contact with valve member 84, float 86 drops back to its original position on stem-62, carrying with it valve member 82, which drops away from valve seat 16. This action assumes, of course, that there i inwmcie'nt water in valve shell 66 to provide buoyancelto fioat86. If enough'water were presentin she'll 66 to support the float, the latter would'not drop "away. Instead, the valve at I6 would remain sealed. this position, port '14 is now sealed at its upper "end only. It will be noted that throughthis seque'nceof operations, port I4'has been closed.

As-long-as'the on .part of the heating cycle continues with the resulting high pressure, the valve will remain in closed condition, as indicated. However, when the cooling part of the heating cycle begins, the pressure within shell 66 will decrease and -'on reaching a pressure which m'ay' be'predetermined through .the proper adjustment of stem62, member 12 will move I downwardly away from valvernember '84, thereby opening port I4 during the time that member I2 is moving to a 'position'of re-engagement with valve member 02. This condition is shown in Fig. '7.

The p'erio'd'during which =prt I4 is open is very brief, but'durin'g that time a certainamount of airtrapped in shell 66 under pressure will escape therethrough and onto the atmosphere throughports --80 and 56.

Each time the heating cycle is repeated, a limited amount of air is vented from shell 66 in the manner just described. The construction is suchthat more air is vented on each heating cycle than'will be distilled .from the water in a corresponding time, so that even though the amount of air vented on each cycle is limited, it still vents rapidlyenough to always keep ahead of the amount of air that'may be trapped. Thus, a radiator containing trapped air will be gradually vented-until it is again'full of water.

Ultimately the water in the radiatorwill rise to such a point that it will-enter the valve through nipple '42 and rise up within shell 66. When it reaches a'certain pointin relation to float 86, the latter will become buoyant so that when the valve attempts to go through the cycle of operations heretofore described, the float will fail to'drop away from seat I6 following the upward movement of member I2 and engagement of valve seat 18 with valve member 84. In consequence, no further venting of air can take place after water has risen to a point within shell 66 to renderfloat 86 buoyant. That is to say, valve seat I6 is engaged continuously by valve member 82 regardless of the pressure that may exist in the air trapped above the water within shell 66 and bellows I0. If, thereafter, additional air accumulates within the radiator, so that the water level within shell 66 drops, then the venting recommences in the manner heretofore described.

In practice, the pressure that is developed during the heating part of a heating cycle in the upper portion of a radiatorcontaining trapped air may easily be measured and the valve stem 62 set accordingly. That is to say, if it were found on a heating cycle that themaximum pressure reached was 30 lbs., while the minimum pressure during the off part of the cyclewas 20 lbs., valve stem "62 will be adjusted upwardly to a point where further elongation of the bellows I0 would not take place until the pressure 'within shell 66 exceeded the minimum pressure required. As pressurewithin shell 66 increases, float 86, valve member '82 and movable member I2 alrmove upwardly'as 'a unit to'engage upper valve member 64-. When the pressure has increased to'ia s'ufli'cient degree; say, 25Ilbs., movable member 12 *comes intoengag'ement with upper-valve member 84, sealing passage 14 at its upper end, whereupon float 86 and valve member"82 fall away from seat I6, as shown in Figs. 6 and 10. As long as pressure in excess of that necessary to elongate bellows I0 sufiiciently to hold movable member -I2 in contact with valve pin 84 is maintained, port I4 will remain sealed by the upper valve. Thereafter, however, when the pressure within shell 66 decreases to slightly less than the elongating pressure of, for example, -25'1bs., member I2, under the contractive tendency of bellowslfi, will commence downwardmovement toward valve pin 82, drawing away from valve pin 84. This condition is shown in Figs. 7 andll. At once the trapped air under compression will begin to escape through port I4. As this action goes on, resulting in a decrease of pressure within valve shell 66, bellows I0 contracts and member I2 moves downwardly, increasingthe space between upper valve member 84 and member I2. When the latter 'reaches a certain point in relation to valve pin =82, float 86-lifts to drive pin 82 against seat ?I6,' thereby-closingport .14 against further egress of air therethrough.

In this manner, limited amounts of air are vented'during each cycle. The amount that is vented is determined by the size of the various portsand *the pressures under which the valve issetto operate. 7

It-is apparent that the valve may be readily adjusted for use with systems using widely varying pressures and on particular radiators 'in which the pressures vary in accordance withthe elevation. -It=is apparent that valve 26 could be directly connected to the radiator by a suitable L fitting, but' since at the start of a heating season it is desirable to fill the radiators completely and quickly, we prefer to use a special fitting 28 for the'connection, which is shown in Fig. 3.

'A brokenzaway section of radiator is shown at I00 having-a threaded hole therethrough at I02. Into this hole is screwed the threaded tubular member I04 having-a port I06 including a valve seat I08. Gonnecting with port I06 is an upwardly extending internally threaded connection IIO-adapted to receive nipple 42. Screwed in a threaded aperture IIZ opposite port I06 is a valve pin I'M. It is obvious that when valve pin -I.04-is screwed inwardly, it will be in engagement with seat I08 to close the port I66. When it is screwed outwardly, port I06 will be opened so that water or air may .pass from the interior of the radiator to nipple 42.

In order that the threaded connection with the pin II4 may be water-tight, a packing H6 is provided, maintained in place by a cap I I8 in screw-threaded engagement with member I04, as shown. At the commencement of a heating season, the operator will unscrew valve 26 from connection H0, port I06 being closed at this time;

Then when water is admitted to the system, valve pin II4 may be unscrewed to'vent quicklyv any air that may be trapped in the radiator. When water appears at connection H0, valve pin II4 will be screwed inwardly to close port I06 to prevent any overflow; Valve 26 is then screwed tightly into position in connection I I0 and finally valve pin H4 is unscrewed to open port I06, in which condition it remains for the rest of the heating season. The automatic operation of valve 26 thereafter takes care of any subsequently trapped air.

From the foregoing description of the heat.-

ing system and the particular type of venting valve that is used, it will be seen that the method of venting the system comprises first heating the water to cause expansion thereof, which in turn results in compression of the trapped air. This compression in turn, acting on an expansible member, results in -a slight increase in the space in whichthe air is trapped. Thereafter, as the heat is discontinued and the water contracts, thereby commencing a reduction in the pressure of the trapped air, a valve is momentarily and automatically opened'to permit the escape of a limited amount of air while the exp'ansible container is returning to its original position of minimum volume;

Thus it will be seen that the method of venting the air is concerned with compressing the trapped gas, expand-ing the container within which it is held and then reducing the container size while at the same time opening a valve to the atmosphere so that part of the gas will be expelled. Thus, by repetition of these steps, excessive amounts of trapped air are gradually eliminated. It is understood, of course, that the air is eliminated at a rate greater than it is distilled from the water of the heating system. A'modified form of the valve is shown in Figs. 8 to 11. This consists of a base I20adapted for connection with a radiator on which is mounted a shell I22 carried by a perforated plate I24 fixed in turn to the base by'lock nut I26. A screen I28 serves to'filter out objectionable substances.

Plate I24is centrally threaded and screwed therein is adjusting stem I 30 on which rests a float I32. Shell I22 has a port I34 to the atmosphere and is closed at its upper end by an internally extending flange I36 soldered or otherwise secured to the shell at I38 and on which is screwed a closure cap I40.

Interiorly threaded to flange I36 is a plug I42 which in turn is centrally threaded at I44 to receive a threaded adjustable valve pin I 46. From this construction, it may be seen that upon removal of cap I40, valve pin'I46 may be adjusted as the circumstances require.

'An annular plate I48 is secured interiorly of the shell I22 by soldering or in any other pressure-tight manner. For the purpose of facilitating assembly, beads I50 and I52 have been provided in shell I22 which enable flange I36 and plate I48 to be quickly and accurately positioned.

Mounted on plate I48 is a bellows I54, to which atthe top is secured a valve member I56 having a port I58 therethrough. 'This valve member has a circular fiange I60, the lower rim of which acts as a valve seat I62 for engagement with a valve disk I64, of rubber or other suitable material, carried by a valve plate I66 having a circular flange I68 that corresponds to flange I60. Plate I66 is fixed to a valve stem I10, which in turn is mounted on float I32. The upper end of valve stem I terminates in a guide h v V The upper edge of port I58 serves as a valve seat I12 which may be engagedby valve pin I46. A spring I14 exerts a downward force on valve member I56. The spring pressure may be varied by adjustment of plug I46 so that the pressure within chamber I16 required to elongate bellows I54 may be controlled.

During the non-heating part of the cycle, the valve is in the position shown in Fig. 8. Thereafter, during the heating portion of the cycle, as the heat increases and the pressure in cham-' ber I16 becomes greater, bellows I54 will be elonshown in. Figs. 2

gated and valve member I56 will move upwardly until valve seat I12 comes into engagement with valve pin I46. The lower valve will, of course, remain closed and the condition of the parts at this time is shown in Fig. 9.

Thereafter, the lower valve will open and the air trapped in chamber I16- will be held there by continued closure of the upper valve. When, however, the heat is discontinued and the pressure-recedes sufllciently,-bellows I54 will contract, opening the upper valve. When this takes place, both the upper and lower valves will be open so that a limited-amount of the trapped air'may escape. Finally, the lower valve closes when rim I62 seats 'again'on valvedisk I64. This closure maybe due either to movement of valve member -.I56 to its lowermost position, as shown in Fig. 7, or it may be due to alifting of float I32 from its adjusting stem support. The latter condition can happen if the clearances are so adjusted that the velocity head of the air past the lower valve disk and plate is sufficient to raise the latter to a position to meet the descending valve member I56.

Through proper setting'fof adjusting stem I30 and valve pin I46, the movement of valve member I56 and the resulting valve opening may be definitely controlled. Similarly, adjustment of plug I46 enables the pressures at'which bellows I54 elongates to be set to any figure'required by the particular-system 'with which the unit'is used. 1

The provision'of-the adjustable upper valve pins 84 and I46 'makes 'it'possible'to manually cause the venting of 'air' from the radiators. Thus, at the beginning of a heating season, when a radiator i likely to contain considerable trapped air, it is possible tovent the radiators in the following manner. Referring to the construction in Figs. 8 to '11, the procedure'is, this. Cap I40 is removed and a screw driver or other suitable tool is'then inserted in the slot in the upper end of the "valve pin I 46, the latter then being screwed downwardly to engage valve seat I12; As-soon as'this happens, valve disk I64 will drop away from rim I62, opening the lower valve. Then, by rotating valvepin M6 in the opposite direction to open the upper valve, there will be momentary escape of :air through port I56. Immediately thereafter, however, the pres sure within the casing and the velocity of gas through the valve will cause float I32 and connected valve disk I64 to move upwardly to seal the lower valve. Valvepin I64 is then screwed downwardly again to close the port at the upper end, whereupon float I32 falls away in the manner previously described. Thus,-by repeated up and down movement of valve pin I46, the radiators may be vented. This assumes, of course, that the air in the radiator is under enough pressure to cause venting.

Operation. of valve pin 84 in the construction to 7 would accomplish the same result.

A further modification of the valve structure is shown in Fig. 12, althoughirifgeneral the principle remains the 'Sameasthoseheretofore disclosed.

It will have-been observed that, in the construction shown in Figs. 2to 7'and8 to -10,'the' upper valve pins 84 and I 46 are'manually adjustable withrespect to their corresponding upper valve seats. By such adjustment the. distance that the members 12 and I56 must 'move before engagement with the upper valve. may be controlled.

The construction; of Fig. 12- varies this to; the extent that the upward movement of the valve member before engagement with the upper valve pin is limited to, a: maximum on each cycleof operation. This will become more apparent as the description proceeds.

The casing I80 houses the valve mechanism the sam as the previously described-casings- 66- and I22. An expansible bellows I82 is secured therein, bein closed t i s top b he a ve member 4 having a p t I86 r t ush. At-the er ns r the po t is a valve s t I8 a the. u pe may include a seating-member I92to forma end a valve seatlfil).v The lower valve seat- I88 tighter seal with valve memberI94 mounted on a float I96similarto-the floats heretofore described. Lower valve'seat I88 is normally in engagement with valve I94 during the cOolin part oithe I heating cycle, as the contractive force of bellows I82 is sufiicient to hold it in such position,

Mounted on the valve member I84 screw threaded connection is a cap I98 centrally ,per iorated at 200 and having side ports 202 and 204.

Extending downwardly into th confinesofcap I98 is a valve member 206 having a valvevseatenv gaging head 208. This head is somewhatlarger than the perforation 200 so that downwardmovee ment of cap I98 will cause engagement of-the cap flange and valve head 208.

Valve member 2061s maintained in position by a pair of shoes 2H] and M2 which frictionallyengage the sides of the valve stem. These shoes are urged toward the valve stem by springs 214 and 2I6 maintained in position by spring holders 2I8 and 220. The force of the springs 2I4 and 2I6 against the shoes is suificient to hold valve stem 206 against movement except .as upward or downward force is applied to it thro ugh movement of valve member I84.

The operation of this construction is aslfollows.

During the heating portion of..the cycle, asthe pressure increases within the; casing, bellowsl82 is elongated, moving valve member I84 upwardly, but port I86 remains closed because thepressure conditions that prevail within the lower partof the casing, cause float I96 and attached valve I94 to remain in engagement with valve member I84 during the latters upward movement. In due course, the upper valve seat I90 will engage valve pin head 208 and thereafter, if further upward movement of valve member I84 takes place, valve stem 206 will slide upwardly between shoes 2I 0 and 2I2.

As soon as the upper .end of port I86 is closed, valve I94 will drop away, as in the case of the other forms, the valve remainin sealed by the pp valve pi o y. ere f e a the r ssur in the system decreases, valve member I84 will drop away from valve 208, which is heldtightly enough by shoes 2 I0 and 2 I2 to allowsu ch action, thereby permitting. the instantaneous escape of gas through ports 202 and 204 to the atmosphere through casing port 222. This instantaneous escape takes place whilelooth valves I 84 and 208are out of engagement with their respectiveseats on valve member I84. When the contraction of bele lows I82 has proceeded far enough, cap I98-1will engage valve head 208, thereby drawing the upper valve downwardly as further reductionof-pressure in thevalve occurs. -It is believed obvious that when this condition-has set in, the distance between valve head 208 and valve seat I90 will have reached a maximum and will thereafter-remain constant. That "is to say, when upward movement of valve member LI84 com-mences on each succeeding-cycle',- the distance valve seat 490 mist m veaibo ere en a men with; a v n ed 298 Wi l-be-un mrm a d1 ell s sl re i l? plate after valv m m fiihasom v t eeee e sary predetermined distance, and further adjustmentwill be unnecessary.

We claim:

1. An air venting valve of the class described om ri n a o i e bovine an in e qe tedi nn t n i h-th te m th t i is? ou ed and a p l ad n to t a m sphe e said port being; formed by an aperture-titre h am ab e membe e ed to ai a inebif ressu e m able mea s? a valve memb r ensto i ith -san t o en m l o n a e: men h ai ova be to lose ai po t. me ns 9 v a al e memb r 29+ ar lv w t said mo l m e hen h el t tor is is lac d. u de di ions of ncreasin ssur W th n s i casing, as v ndvalv meme er nosit oneoleio n a em n thid me ble member t clo eai t en-sai m rab e er 1. 1 mqved ardl a .QF QEWI E o st o o om its o a lw i-ti lt th s n c t nb ee su hhat i t n a iv -member wi l retu n t i s r ein o t on lowin osin f 3 i 11 0 b i ewn v ve V-m mb r 591 b??? a d pert lbe mom r en i e vrer tu moveme of sa ova l mem e from s' p e closed posiiioe a a ns sai so nd; alve W 9.33 Q Qf Pos o a ain saidfir t-velv member.

e ve for r et ne i ir m ho at r stem Wh Ph' h -We e iis hea nt rmi teat Y1 mpri n a a n having: a inlet a id-e so t e-t o tmo phere r fl n i l ll in a m lle ltiq ha a m mb ith an ev r- We h re rough aifiXodth ret val e: o re b 'wiihn fi ii ca n t e n rme lr inrl neaee; mee w th some m v le mem er: to los I e a er ure der q i ns -lov. ressure an in 9 Q Wat r ;r ?i va ve em e unror odla a n td wnwar t ier-men from its normal position butoapableo f move ment upwardly with said mgr/able memberanda s cond va ve m be t oned b v on normo l out o em n with S i :mov ble me ne her, the movable portion of said casing being capable of suff cient motion to permit said move able memberrto be forced into engagement ith said secondvalve member upon the applicat' n of suificient pressure within said casing, thelgc on t u on be ng u tha sa fi st-V l e memb will, return to its original: position; following clos ine of said rtu o y aid ewnd' v member so that said aperture will be momentarily Opened r g, r urn: m vemen said m vab m e m t ar l sro qn a ainst said second valve member to normal closedposition against said first valve member. u

3. A valve for venting air from a hot water system i'nwhich the wateris heated intermittently, comprising a s ne if- 1 1? v w eemhe m d i t -d rd mov m n an p rabl of upward movement,- a second valve; member maintained in fixed position, amovable member having an aperture therethrough and normally in engagementwith said 'firsti valve member to closeesajid aperture, said'first valve member and said movablemember capableof joint movement under the influence of, sufiicient pressure within said casing toward :said second valve member until ;the lattersghas c 1osed. said aperture by enga e.- ment withsaid movable'member, the construction being, such ,that saidzfirstwalve member will return ;to its original position ,following closing of said'apertur'e by said second valve member so that s aid aperture will be momentarily opened during return movement of said movable memher from its upper closed position against said second valve member to normal position with respect to said first valve member.

51. A valve for venting gas from a hot water system in which the water is heated intermittentlyQcomprisinga casing divided into upper and lower spaces by a bellows, said bellows having; mounted thereon an apertured member throughwhich gas may pass from the lower to the upper space, a'port from the upper space of said casing to the atmosphere and. means'for connecting the lower space of said casing to said system, a float supportedwithin the lower area of said casingand having' mounted thereon a valve member, said float and valve member being free to; move upwardly-- under suitable conditions of-gas pressure or water level within the lower space of said casing while continuously in engagement with said apertured member to prevent the passage of gas from the lower to the upper space, and a second'valvemember located closely above said apertured member in fixed relation to said casing and adapted to engage and close said apertured member when the latter has moved upwardly thereagainst, the construction being such that immediately upon engagement of said apertured member and said second valve member and when insuflicient water is in the casing to hold said first valve member closed, said first valve member and float will fall away thereby opening said apertured member on the lower side. 5.- Valve mechanism for use in a valve for venting air from a'hot water system in which the water is heated intermittently, comprising a bellows, a valve member connected thereto and having-an aperture therethrough; one end of said aperture terminating in an annular valve seat larger than said aperture, the other'endof said aperture terminating in a valve seatsmaller than said annular valve seat, a valve for engaging said annular valve seat comprising a valve disk and an upwardly extending guide long enough to enter saidaperture without closing the'aperture to the'fiow of air, and a vavlve for engaging said second valve seat comprising'a valve pin, and means for supporting said valves, said first valve being movable toward and away from said second valve;

1 6. Anair venting valve as set'forth in claim 1, having means for varying the resistance of said pressure movable means to the influence of pressure developed within said casing.

-7 A valve as setforth in claim 2, having spring means for exerting a force against said apertured member in the direction of said first valve member. 8. A valve for venting compressed air, comprising a casing, a first valvemember within said casing, a stop for limiting the downward movement of said first valve member, a second valve member maintained in adjustable relation to said casing, a movable member closing said casing positioned between said first and second valve members having an aperture therethrough, said aperture arranged to be completely closed by eitherof said valves, the area of-said aperture said'closd position when the aperture is closed at'its other end by said second valve member.

9. A valve for venting compressed air from a hot waterheating system capable of either manual or automatic operation, said-valve comprising a casing, a first valve membermovable upwardly, a member closing saidcasing and movable under varying pressures within said casing, said member having 1 a single aperture therethrough adapted to be closed completelyby said first valve member when in engagement therewith, a second valve memberpositioned opposite said first valve member and adapted toclose completely said aperture in said movable member when the latter has 1 been brought into engagement therewith, the area of said aperture bearing a relationship to said first valve member such that under conditlons of' increased pressure that may prevail in-said casing,- said first valve member will be raised from its seat to close said aperture, said second valve member manually adjustable with respect to said aperture, the construction being such'that said aperture may be closed by said second valve by either an increase of pressure within said casing sufl'icient to drive said movable member against said second valve member or by manuallymoving said second valve member-into engagement with said movable member, the relationship of all the partsbeing such'that whenever said aperture is closed by said second valve member, said first valve member will fall away from said movable member to open the inner end of saidi'ape'rture.

10. A valvefor venting'air from a hot water heating system, as set forth in claim 9, in which said first valve member is mountedonr afloat wherebysaid aperture will be continuously closed by said first valve member after water has risen within said casing a distance suificient'to render said fioatbuoyant. "11. A valve for venting air froma hot water system in whichthe water is heated intermittently, comprising a casing having an inlet and a port to the atmosphere, said casing including a movable'portion having a member with an aperture therethrough afllxed thereto, a valve member within said casing and normally in engagement with said, movable member to close said aperture, said valve member limited in its'downward movement from its normal position but capable of movement upwardly with said movable member, and a second valve positioned above and normally out of engagement with said movable member, the movable portion of'said casing beinglcapable of sufficient motion to permit said movable member to be forced into engagement with 'said second valve member upon the application of sufficient pressure within said casing, said second valve member movable, upwardly after'fen'ga'gement with said movable'member upon iurther upward movement of the latter, and means connected to said movable member for drawing said secondyalve member downwardly after said movable member has fallen away from said second valve. member a predetermined disa e-r, V 12. H valve asset forth in claim 2,.inwhich the second valve member is movably maintained in position to permitupward and. downward movement thereof under the influence of said mo abl memb r- 1.1-. r

said-secondvalve member is movably maintained in position; whereby *itm vm ve .upwa d .af r en a ement/with iseid' mo ble m m and means associated with said movable member whereby said second valve member may be drawn downwardly upon downward movement of said movable member after the latter has fallen away a predetermined distance from said second valve member.

14. A valve for venting air from a hot water system in which the water is heated intermittently, comprising a casing, a first valve member limited in its downward movement and capable of upward movement, a second valve member maintained in fixed position in alignment with said first valve member, a movable member having an aperture therethrough and positioned between said first and second valve members, said aperture adapted to be completely closed upon engagement of said member with either said first or second valve member, said movable member adapted to engage said first valve member under condi-, tions of relatively low air pressure in said casing to close said aperture, said first valve member and said movable member capable of joint movement under the influence of increasing air pressure within said casing toward said second valve member until the latter has closed said aperture by engagement with said movable member, said first valve member constructed to fall away from said movable member immediately upon closure of said aperture by said second valve member.

JOHN UPTON. WARREN T. FERGUSON. 

